Disconnecting contact



. 2, 1941. M. J. RUBEL EIAL DISCONNECTING CONTACT Filed Sept. 9, 1959 2 Sheets-Sheet 1 KTTORNEY INVENTORS Ce:

ll BY if V a 2 1 L WITNESSES! Patented Dec. 2, 1941 DISCONNECTING CONTACT Max J. Rubel, Pittsburgh, and Harold H. Rugg,

Wilkinsburg, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 9, 1939, Serial No. 294,118

4 Claims.

installed.

A more specific object of our invention is to provide a disconnecting contact of the plug and socket type suitable for connecting round I current conducting members.

Another object of our invention is to provide a disconnecting contact which shall have a high current carrying capacity and shall be suitable for use on high voltage power systems.

A further object of, our invention is to avoid a the use of flexible current conducting members or shunts in a disconnecting contact.

Still another object of our invention is to provide a disconnecting contact in which equal pressureis produced at each contact point.

A still further object of our invention is to provide aiull floating disconnecting contact to permit a relatively large amount of misalignment between the connected members in all directions.

Other objects of our invention will be explained fully hereinafter or will be apparent to those skilled in the art. In general, the disconnecting contact embodying our invention comprises a moving contact and a stationary contact. The moving contact utilizes the stud of a circuit breaker as a contact and supporting member for a plurality of contact fingers disposed around the stud. The contact fingers are equally spaced around the periphery of the contact surface by a spacing plate. Contact pressure is provided by a plurality of helical springs spaced along the contact fingers, which are retained on the breaker stud by engaging shoulders on the fingers and the stud. The stationary contact comprises a round plug inserted within the cylindrical opening provided by the contact fingers.

For a fuller understanding of the nature and objects of our invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a view, partially in section and partially in elevation of a disconnecting contact embodying our invention;

Fig.'2 is a view, in section, taken along the line II-II of Fig. 1;

Fig. 3 is a view, partially in section and partially in elevation, of one modification of the invention;

Fig. 4 is a view, in section, taken along the line IVIV of Fig. 3;

Fig. 5 is a view, in elevation, showing the disconnecting contact members in a misaligned position;

Fig. 6 is a view, partially in section and partially in elevation, of another modification of the invention; and

Fig. '7 is a view, in section, taken along the line V'IIVII of Fig. 6.

Referring to the drawings, and particularly to Fig. 1, the disconnecting contact shown therein is comprised of two parts, a moving contact Ill and a stationary contact II. The moving contact I0 comprises a round stud l2, which may be part of a circuit breaker structure (not shown), a plurality of contact fingers l3 disposed around the periphery of the stud l2 and a plurality of helical springs l4 bent into ring formation to bias the contact fingers inwardly to maintain contact pressure between the stud l2 and the fingers I3. The circuit breaker stud l2 may be secured to an insulating panel It by means of a spanner nut I6.

A keyway I! is provided in the stud l2 for receiving an inwardly extending projection l8 on each of the contact fingers l3. Thus, the projection l8 engages the sides of the keyway ll to retain the fingers IS on the stud l2. It will be noted that the keyway I! is wider than the projection is, thereby providing a clearance I9 between the edge of the keyway and the shoulder I8 to permit longitudinal motion of the contact finger. In this manner, a. desirable contact wiping action is obtained between the contacting surfaces of the fingers l3 and the stud l2.

The contact fingers l3 may be equally spaced around the periphery of the stud l2 by means of a spacing plate or washer 2|, as shown in Fig. 2. The spacing plate 2| is provided with equally spaced radial notches 22 for receiving the contact fingers 13, thereby maintaining the fingers in spaced relation and also keeping them' in a radial position.

The springs I4 may be equally spaced along the contact fingers [3, each finger being provided with grooves 23 for the springs ll. It will be seen that the spacing plate 2| is so lo cated that a larger number of springs are on the moving circuit breaker stud side of the plate than the spacing plate inward movement of the disengaged ends of the contact fingers when the moving contact I is removed from the stationary contact ll.

Therefore, there is a definite tendency to hold the contact fingers firmly against the circuit breaker stud I2 when the contact is in the disconnected position. However, when the contact is in the engaged position, as shown in Fig. 1, the spacing plate 2! floats between the fingers and does not act as a fulcrum point for the contact fingers. The contact fingers are then firmly pressed against the contact surfaces 24 and 25. Since the springs It are equally spaced on the contact fingers 13, equal pressure is produced at the contact points 24 and 25, the contact on the stationary stud side. Furthermore,

fingers l3 functioning as beams with uniformly distributed loads.

The stationary contact H comprises a round plug 23. into one end of which copper blades 21 may be inserted to provide for the conventional method of connecting to bus bars. The plug 26 may be secured to an insulating panel 28 by means of a spanner nut 29, similar to the nut l6.

As shown in Fig. 5, the contact assembly is full floating and permits a relatively large misalignment in all directions between the circuit breaker stud l2 and the stationary plug 26. Since a large misalignment between. the circuit breaker stud and the stationary contact can be accommodated without detriment to the current carrying capacity oi the contact, it is possible to eliminate many expensive jigging operations in the manufacture and the assembly of metal switchgear structures containing removable circuit breaker units. In this manner, the cost of 2! is designed to limit the manufacturing and assembling switchgear of this type may bematerially reduced.

Furthermore, the use of flexible shunts in the contact structure is entirely avoided, thereby further reducing the cost. Also there is no possibility of trouble being caused by poor soldering since there are no soldered connections in the structure. It will be seen that the current passes directly through the contact fingers l3 from the one contact stud to the other, without going through flexible shunts or soldered connections.

In the modification of the invention shown in Figs. 3 and 4, which was designed for lighter duty than the structure described hereinbefore, the contact fingers l3 are semi-circular in cross-section. Furthermore, the fingers are bent orcurved at each end to engage the studs and also to provide seats for the springs M.

The stud I2 is provided with a shoulder 3| to prevent the contact fingers from sliding off the stud l2 when the moving contact is removed from the stationary contact. If desired, the spacing plate 2| may be secured to the stud it by means of a screw 32, as shown. The stud i2 is secured to the panel l5 by means of a nut 33 and the plug 23 is secured to the panel. 28 by a similar nut 34.

In the modification of the inventio shown in Figs. 6 and '7, which was designed use with high potential circuit breakers of the vertical. lift type, the moving contact I0 is carried by circuit breaker bushing 35 and the stationary contact II is mounted inside of a cylindrical sleeve 36, which may be composed of porcelain or other suitable insulating material. The lower end of the sleeve 36 may be cemented in a flanged supporting ring 31 which is secured to a metal plate 38 disposed at the bottom of the superstructure An internal flange 39 is provided in the sleeve 36 to which the plug or stud 26 of the stationary contact is secured. As shown, the flange 39 is clamped between a shoulder II on the top of the stud 26 and a nut 42 which may be drawn tightly against the bottom of the flange 39. The stud ll of the moving contact I0 is threaded into the breaker bushing 35 and locked by means of a lock nut 43.

The structure of the moving contact shown in Fig. 6 is similar to that shown in Fig. 1 with the exception that the fingers l3 are'somewhat longer and, as shown in Fig. 7, more fingers are provided. Also, as shown in Fig. 6, more springs H are provided to increase the contact pressure, thereby .making a contact assembly having a high current carrying capacity. In this modification the springs lt are so disposed on the Tim gers l3 that a higher contact pressure is maintained between the fingers l3 and the stud l2 than between the stud 26 and the fingers.

From the foregoing description, it is apparent that we have provided a disconnecting contact which is simple in structure, low in cost and has a high current carrying capacity. Furthermore, the present structure permits a large misalignment between the moving contact and the stationary contact, which makes it particularly suitable for use with truck type and other removable circuit breakers.

In compliance with the requirements 0! the patent statutes, we have shown and described certain embodiments of our invention. However, it is to be understood that the invention is not limited to the precise constructions herein shown, the same being merely illustrative of the principles of the invention.

We claim as our invention:

1. A disconnecting contact comprising a round stud, a plurality of rigid contact fingers movably disposed around the periphery of said stud in spaced relation, resilient means for maintaining contact pressure between the stud and the fingers, means on the stud cooperating with means on the fingers forretaining them in position on the stud, and a plate supported entirely by the fingers and having radial notches therein for retaining the fingers in a radial position and in spaced relation around the stud, said fingers having means thereon for retaining said plate in position.

2. A disconnecting contact comprising a round stud, a plurality of rigid contact fingers movably disposed around the periphery of said stud in spaced relation, resilient means for maintaining contact pressure between the stud and the fingers, means on the stud cooperating with means on the fingers for retaining them in position on the stud, and a circular plate disposed inside of the fingers and having a radial notch on its periphery for each one of the contact fingers to retain them in a radial position and in spaced relation around the stud, said fingers having notches therein for retaining said plate in posiion.

3. In a disconnecting contact, in combination, a plug and a socket for receiving the plug, said socket comprising a circular stud, a plurality of individual rigid contact fingers movably disposed around the periphery of said stud in spaced relation, a plurality of helical springs for biasing the fingers inwardly into engagement with the stud and the plug, a floating washer disposed inside of the fingers for equally spacing said fingers in a radial position and for limiting the inward movement of said fingers when the plug is removed, and means for retaining said washer in position.

4. In a disconnecting contact, in combination,

a plug and a socket for receiving the plug, said socket comprising a circular stud, a plurality of contact fingers movably disposed around the periphery of said stud in spaced relation, a plurality of helical springs for biasing the fingers inwardly into engagement with the stud and the washer in position.

, MAX J. RUBEL.

HAROLD H. RUGG. 

